Dual spray nozzle for fuel burners



July 24, 1951 R. G. MESCHINO DUAL SPRAY NOZZLE FOR FUEL BURNERS 2Sheets-Sheet 2 Filed Dec. 30, 1948 (7111x1170? KW ,yrn

Rona/ G. Msczi-na Patented July 24, 1951 DUAL SPRAY NOZZLE FOR FUELBURNERS Ronald Guerin Meschino, Toronto, Ontario; Canada, assignor to A.V. Roe Canada Limited, Malton, Ontario, Canada, a corporationApplication December 30, 1948, Serial N 0. 68,291

I 9 Claims.

This invention relates to improvements in fuel burners and in particularto burners for the combustion chambers of gas turbine engines.

'In a gas turbine the fuel is injected into an air stream which has ahigh speed of flow and in order to obtain efficient combustion it isimportant that the fuel'should be thoroughly atomized and distributed asevenly as possible across the air stream. It is also important that goodatomization and distribution should be obtained at all speeds throughoutthe range of operation of the turbine and at all rates of fuel flow.

Atbmization is commonly achieved by arranging the various ducts andchambers inside the burner so that the fuel in the burner is caused torotate at a very high speed before emerging from the nozzle of theburner into the air stream. This rotation results in the fuel beingsprayed from the'nozzle in a cone of fine particles, but variations infuel pressure and rate of flow directly affect this atomization and atlow pressures the swirling of the fuel is reduced to such an extent thatatomization is seriously impaired. Various devices have been adopted toovercome this difliculty and of these the so-called spill-type burner isperhaps the most effective. In the spillty'pe burner the supply pressureis preferably kept constant, thus ensuring constant rate of swirl;

and-fuel in excessof requirements at thenozzle allowed to return to thetank through a controlled outlet line. Although this type of burnerovercomes some of the chief problems of atomization, a single burner isliable'to cause too greata concentration of fuel in limited areas'of the'air' stream at high rates of flow, resulting in inefii lem; combustionand waste of fuel. To meet this di'flicultya number of burners canbelemployed';

but unless these are arranged'co-axially in the combustion chamber theircones of particles over lap; causing an uneven patternof fueldistribu'-' tion. In any case, the use of a multiplicityiof burners ofthe usual type is liable to be cumbersome. Furthermore, in all knownforms of burn j ers utilizing a swirl of fluid inside the burner, the

swirling fluid and the air core which is created by the swirl mustimpinge at the inner end on the rear wall of the swirl chamber, whichmay be either'a' fixed wall or a wall of fluid in the spill passage.Consequently an undesirable drag effect is caused, and the air-core islikely to become unstable; causing corresponding instability of thespray.

e'r'in which two nozzles arearranged. co-axially' sucha way as toeliminate therinstabilityof An object of thisinvention isto provide aburn? flow which is inherent in all types of burners hav ing one or moreindependent swirl chambers.

A further object of this invention is toob'- tain improved atomizationat lower inlet pressures, for any given rate of flow, by the use of twonozzles supplied from a common feed and in the case of the spill-typeburner controlled through a common outlet line. Y

All of the foregoing and still further objects and advantages of theinvention will become apparent from a study of the following specifica-'tion, taken in conjunction with the accompanying drawings, wherein likecharacters of-reference indicate corresponding parts throughouttheseveral views and wherein: Fig. 1 is a side view of a spill form ofburner constructed in accordance with this invention;

- Fig. 2 is an end view of the said burner;

Fig. 3 is a cross sectional view on the line- 33 ofFig.2;' Fig. 4 is across sectional view on the line 4-4 of Fig. l; 1

Fig. 5 is a cross sectional view on the line 5-5' ofFig.1; Fig. 6 is alongitudinal vertical cross sectional view of another form of burner,namely,- a burner of-the duplex type, constructed in accordance withthis invention; i Fig. 7 is a cross sectional view on the line 1'| ofFig. 6; and i v Fig. 8 is a cross sectional view on the line 8-8ofFig.6. I The spill burner illustrated in Figs. 1-5 comprises a body,indicated generally by reference numeral l0, thesaid body beingcylindrical inshape and being supported in the combustion chamber of agas turbine by inlet and outlet pipes II and I2 respectively. Atopposite ends of the body are nozzle orifices l3 and I4 and the burner.is so placed in the combustion chamber that its. axis lies substantiallyparallel to the flow of air through the chamber. as indicated by thearrow. A, the nozzle orifice I3 facing downstream. of; the air flow andthe, nozzle orifice l4 facing upstream. The body Ill includes acylindrical barrel member l5 having a thick-walled portion IS in whichan outlet orifice I! is provided; registering with the orifice I1. andsecured to the thick-walled por. tion I 6 of the barrel member I5 is asleeve it which receives an outlet pipe l2. Seven longitudinallydisposed passages l9 are provided. in, the barrel member, these beingsymmetrically arranged around its axis. The thick-walled 'por--'. tionI6 of the barrel member is formed with an annular recess 20, and annularshoulders 21 and 2! which indirectly engage (being in practice spacedtherefrom by packing glands) with the inner ends of central tubes 22 and22 extending downstream and upstream respectively. The barrel member hasat the upstream end an annular stepped portion 23 and an externallythreaded extension 2d,. and has at the opposite end an outer annularshoulder 25 which engages with a. second barrel member 26 in which anin-- let orifice 2? is provided; registering with the orifice 21 andsecured to the barrel member 26' is a sleeve 28 which receives an inletpipe Ii. The second barrel member 26 has. at the downstream end anannular stepped portion 26 and an: externally threaded extension 26?.Closely fitting,

over the outer ends of the central tubes 22 and 22 respectively are theend blocks 30. and 31")" in which are provided the nozzle orifices l3and UL co-axially communicating with tapered swirl chambers ti and. 3!.The swirl chambers are connected to annular recesses 32 and 32 by ports33. and 33' respectively, the. ports entering the swirl. chamberstangentially as shown in Fig. 4. The end. blocks 30, and 3d are held inplace-by internally threaded caps 34 and 34 which are. screwed on theends of the barrel members 26 and. 1:5 respectively.

It will be seen that the arrangement of parts of. the body at thedownstream end defines an annular chamber 35 having a relatively narrowannular recess 32; and at the upstream end defines an. annular chamber35 having a. relatively narrow annular recess 32-. The two chambers 35and 315' are interconnected by the longitudinal passages l9, and.chamber 35 is connected to the swirl chamber lit by the tangential ports33 whereas; chamber 35' is connected to the swirl chamber 3| by thetangential ports 33". The Swirl chambers 31. and 3t areconnected:through the open passage constituted by the bores. 36 and; 3.6- of. the.central-tubes 22; and 22:, respectively, and by the central cylindricalchamber 31, which, is. defined by the annular recess the bores. 36; and.36 are chamfered'. atifie and 36? respectively. The diameter of-thebores 36; and 36 is less than the diameter of ;the:swirl-, chambers 3Land 3t but materially greater than the diameter of either of the nozzleorifices-113 and 14. The. central! chamber! 31.- communicates w.ith= theoutlet pipe [2.

-In the operation of: the spill burner, fuel under high pressure enters.the burner through; theii-nlet pipe H and fillsrthe: downstream annularchamber 3.5, passing through the:longitudinalpassages [.9 to fill thecorresponding upstream. chamber Considering-first the operation of thedownstream end of theburner, it willlbezapparent thatfuel from the.chamber 35% flows: through the ports. 33 into the swirl" chamber-.31;Since the ports. 33 enter the swirl chamber'3l. tangentially liketorque-inducing directions, the incoming flow of fuel is-g-i-vena rotarymotion, and under the high pressure applied the speed of rotation isvery great. The fuel emerging from the nozzle orifice l 3-isin the formof a conical spray of finely di-- vlded particles 38. Fuel in excessofrequirements is spilled off through the bore 36 to the central chamber3!- whence it may be allowed to escape through theoutlet pipe I2. Bycontrolling the outletfl'ow by a suitable valve it is possible tocontrol the depth or thickness of the rotating layer of fuel in theswirl chamber 3| and thus oft-he burner.

4 orifice l3. The inlet pressure is maintained at an approximatelyconstant value throughout the range of fiow required.

In the same manner, fuel is introduced into the upstream swirl chamber 3l through the ports 33 and emerges from the upstream nozzle orifice Hiin a conical spray 38, excess fuel being spilled off through the bore36. to the outlet pipe l2. Thus the two swirl chamber-nozzle systems are1 fed by a common inlet and spill to a common outlet, which provides fora common control of their rate of spill. It will be noted that the ports33 and. 3-3 are arranged in relation to their respective-swirl chambers3i and 3| so that the swirl win each is inthe same direction, that is,anticlockwise when viewed from a point downstream The most importantconsequence of this arrangement is that the two systems have a commonair core 39. In all burners employing the: swirl principle, an air coreis formedaround theaxis. of thev rapidly. spinning, fi-uid and the:stability of the flow from the nozzle. depends; on the stability of.thisv coreu If. the inner. end of this core, that is the end remote fromthe nozzle impinges upon a wall; of. the swirl .chamber or upon: a. wallof fluid. in the. spill passage, it isl-ikely to be unstable at. varyingrates of fiow; stability therefore can only be achievedif. the air coreis open and unobstructed at both ends, and this result is obtained bythe. invention. as herein described. 1

By the employment. of acommon outlet-system and a common inlet pressure,andswirl chambers of equaldiameter, the-depth-oi .iuel in the down--.

streamswir-l chamber 3|. isequal tothe depth oi fuel in the. upstreamswirl. chamber 3| Thusthe: fuel emerging from. the. nozzle orificesHand. II. can be apportioned-by the choice of the diameters of theseorifices, in a manner appropriateto. the

fuel distribution required tor efiici'ent two stage combustion in theairstream.

Another embodiment of the. invention, in which the invention is.applied. to. aburner of the duplex..-

- type,, is shown in Figs. 6,. 7 and- 8. In the. nor- 42. and.43respectivel'y. At opposite end's ofjth'e body 4 Larethe-nozzleorificesiATifand 4'51. directed downstream andupstream; respectively,which are connected; by a singlelongitudinall centralfchamber. 46,.which provides. at opposite. ends. inter connected-terminal; swirlchambers. 41 and '4'T.;;'

it willfbe. noted that the swirl chambers 'arei'n.

practice provided. in end. blocks 48 and"49. barrel member 50,. havingannular channelled portions 51",. 52 andi 5'3 and threaded ends 54? and,51'', is secured around theendi blocks. fli an'vzl'v 49. by threaded endcaps 56- andj56. I

The end' blocks 48"and43'are peripherally chan' nelled. to define,cooperationfwi'th the pegripheral channels 5|. and 53' in ftlie'barrelmemf ber, annular chambers 51 'andf'5'8; 'at'the down: streamandlupstream ends'respectivel'yf The said annular chambers are connectedby'lbngitudin'ali passages 59 which are symmetrically arrangedaround'the axis'of the burner: The primary fuel inlet" pipe"4'2"comnmnicates directly. with;

the quantity of fuel emerging from the nozzle the annular'chamber 51"througlr'the inlet oriflce atencse nected to. the .central chamber 145ivbylports 61, and 62- respectively; which .enter' the; chamber 46tangentially?new 'The'end'block 48 is; also peripherally chan-L nelled'at 148% todefine, in cooperationwith the,

inner faceof .the'end block 49- and the periphera-l g ly-channelledportion .52 in thebarrel member 50,, arelatively small secondaryannular; chamber 63,. with which thesecondary inlet .pipe 43 ;directlycommunicates through the secondary inlet orifice, 64. j.Thesecondaryiannularchamber 63 is connectedsto the central-phamber 46,byvsecondary. portsGEi which, likeeportsfil and. 62, enter thech'amber:.=46 .tangentially.-;-. 1 E

The operationof Atheduple burner ,is similar to that of, the spillburner,- except 'that ,the control of ,the fluid flow is effected bychanges in; pressure in the-:secondary,inletpipe- 43 whichchanges thespeed offlow through thesecondary, ports'65 and thereby directly aifectsthe velocity of swirl in the chamber t6.v The primary ,inlet, pressureispreferably keptsubstantially constant; As inthe spillburner, an air corecommon to both ends of the burner iscreatedand a; corre-p spondingstability of flow is achieved.

It is thought that the construction and use of the invention will beapparent-from the above description of the various parts and theirpurpose. It is to be understood thatthe forms of this invention,herewith shown anddescribed are to be taken as preferred examples "ofthe same, and that=various changes in. the shape, size and arrangementof the parts may be resorted to, without departing from the. spirit ofthe invention: and-the scope of the subjoined claims.

'Wha't I claim as my invention is:

lr A burner for liquid fuels comprisin a body having nozzle orificesatopposite ends, apassageway' withinthe body connecting the nozzleorififices, interconnected annular chambers e'ncircling the passageway,fuel ports leading from the annular chambersand, entering the passagewaynon-radially to'cause a swirling action of the fuel in the passageway,meansjfor conducting fuel from asouroe of-supplyunder pressure to theannular chambers, and a flow-regulating conduit communicating with thepassageway, the passageway being adapted to provide between the nozzleorifices a continuous annular body of swirling fuel having an air-coreextending through both nozzle orifices in the body.

2. A burner for liquid fuels comprising, a body, tapered swirl chamberswithin the body, the swirl chambers terminating in nozzle orificessituated tat opposite ends of the body, interconnected annular chambersdisposed coaxially in the body, fuel ports leading from the annularchambers and entering the swirl chambers nonradially to cause a swirlingaction of the fuel in the swirl chambers, an inlet conduit forconducting fuel under pressure to the annular chambers, an openpassageway connecting the swirl chambers and adapted to provide betweenthe swirl chambers a continuous annular body of swirling fuel having anair-core extending through the nozzle orifices in the swirl chambers,and a flow-regulating conduit communicating with the passageway.

3. A burner for liquid fuels comprising, a body having nozzle orificesat opposite ends, tapered swirl chambers within the body havingcommunication with the nozzle orifices, interconnected annular chambersdisposed co-axially in the body, fuel ports leading from the annularchamv chambers and entering the end portions of the hers-and enteringthe swirl chambers, non-radial ly to cause a swirling action ofthe-fuelv in the, swirl chambers, an inlet conduit for conducting- 5fuel under pressure to the annular chambers, an, openpassagewayconnecting the swirl chambers;

and adapted to provide between the swirlchamaction of the fuel in theswirl chambers, an inlet conduit for conducting fuelunder pressure tothe annular chambers, a central chamber in the body passagewaysconnecting each ofv the swirl chant;

bers to the central chamberand adapted to provide between the swirlchambers a continuous annular body of swirling fuel having an air-pore;

extending through the nozzle orifices in the body,

and a flow-regulating outlet conduit communi eating with the centralchamber. I

5. A burner for liquid fuels comprising, abody having nozzle orifices atopposite" ends, tapered, swirl chambers within the body having commu-,nication with the nozzle orifices, interconnected annular chambersdisposed co-axially in the body, fuel ports leading from the annularchambers and entering the swirl chambers non-radiallyto cause a swirlingaction of the fuel in the swirl chambers, a primary inlet conduit forconduct-. ing fuel under pressure to the annular ch'am bers, a,passageway connecting the swirl cham= bers and adapted to providebetween theswirl chambers a continuous annular body. of swirling,

fuel having an air-core extending through. the. nozzle orifices in thebody, and a. flow-regulating.

secondary inlet conduit communicating with the,

6. A burner for liquid fuels comprising,-abody v having nozzle orificesat opposite ends a passageway within the body connecting the nozzleorifices and having convergingly tapered end portions constituting swirlchambers, interconnected annular end chambers disposed around and spacedfrom the end portions of the passageway, primary fuel ports leading fromthe annular end passageway non-radially whereby a continuous annularbody of swirling fuel having an air-core extending through the orificesin the body is provided, a primary inlet conduit for conducting fuelunder pressure to the annular end chambers, an annular control chamberdisposed around the passageway between the annular end chambers,secondary fuel ports leading from the annular control chamber andentering the passageway non-radially, the said secondary fuel portsbeing adapted to increase the swirling motion of the fuel in thepassageway, and a flow-regulating secondary fuel inlet for conductingfuel under pressure to the annular control chamber.

'7. A burner for liquid fuels comprising, a body containing an elongatedpassageway of circular cross-section for containing a rotating body offuel and having axially directed discharge orifices at opposite ends,the body having two groups of fuel inlet ports leading into thepassageway for delivering rotation-inducing jets of fuel at highvelocity, each group of ports leading into one of theopposite endportions oi the passageway each port entering the passageway non-axiallyanal non-radially and allthe ports in botlrg roups" entering thepassageway in the same rotary" sense, each groupof constituting meanswhereby the jets discharged therefrom: Wiilcause rapid 'vortical motionin the fuel corresponding end ofthe passageway around; core and the twogroups of ports co-operating: to cause theair core produced by eachgroup or parts to merge with the other air core into" a centinuousaircoresurrounded by a continuous annular'bo'dy of swirling fuel andextending to full length of the passageway through bothdischargeorifices, and means for conducting fuel under High pressurefrom a source of supply to thefuelinletp'orts.

8 A burner for liquid fuels eomprising, a body containing an elongatedpassageway of a circular cross-section for containing a rotating body offile-land having axially directed discharge ori-- fi'ces at oppositeends, an annular chamber in the body and encircling the passageway, thebod-y having two groups'of fuel inlet portsleadihginto the passagewayfor delivering rotation-inducing jets of fuel at high velocity, eachgroup of ports leading into one of the opposite end portionsofthe-passageway, each port entering the passageway non-axially andnon-radially and all the ports in both groups entering thepassagewayinthe same rotary sense; each group of ports constitutingmeans whereby the jets discharged therefrom willcause rapid verticalmotion in the fuel in the corresponding" end of the passageway around anair core and the two groups of ports co operating to cause the air coreproduced by each group-of ports tomerge with the other air core into acontinuous air core surrounded by a'continuous annular body of swirlingfuel andextending the full length of the passageway through bothdischarge orifices, means for conconducting fuel under high pressurefrom a source of supply to the annular chamber, and a flow-- regulatingconduit communicating with the passage'way.

9. A burner for liquid fuels" comprising, a'body 8 containing? anelongaten passageway of circula cross s'ecticn for containing a rotatirigwbcdyrofi fuel the oppositeends of the passageway pro: viding swirlchambers terminatinggin axially die recte'd nozzle orifices situated atopposite ends of the body; theabody l'lavmgftwo groups oriuelr. inletports-- leading. i into. the passageway; for de liveringfrotationsinducingijets of fuel at highve locity; eachwgroup ofportsleading into- 'one ofi the switl chambers; each port entering thepasssageway non-axially ariation-radially and alt the ports in bothgroups entering the passageway thesame rotarysense; each group ofportscon stituting' means whereby the. jets discharged therefrom willcause rapid vertical motioninntha fuel iri the corresponding swirlchamber around an air eore and the two groups of ports: co -wer ating tocause the air core produced. by; each; group of portstamerge with: theother aircore'g into a continuous air-Scoresurrounded bya com:tmuousannular body? ofswirlingifuel and extend mg then-11 1 length ofthe passageway thl'dlighiboth discharge orifices, and means for conducte ing fuel under highpressure from a; source at supply to the fuel inletports RONALD GUERIN MESCHINO;

I REFERENCES CITED The following references" are of record in'thq

